Cod sursa(job #2677684)

Utilizator World_shifterMurgu Bogdan World_shifter Data 27 noiembrie 2020 10:37:03
Problema Evaluarea unei expresii Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.14 kb
#include <fstream>

using namespace std;

ifstream in("evaluare.in");
ofstream out("evaluare.out");

const int N = 100001;

char s[N];

int p;
int expresie();
int termen();
int factor();

int expresie(){
    int sum = termen();
    while( s[p] == '+' || s[p] == '-'){
        if(s[p]=='+'){
            p++;
            sum += termen();
        }else{
            p++;
            sum -= termen();
        }
    }
    return sum;
}

int termen(){
    int prod=factor();
    while(s[p] == '*' || s[p] == '/'){
        if(s[p] == '*'){
            p++;
            prod*=factor();
        }else{
            p++;
            prod/=factor();
        }
    }
    return prod;
}

int factor(){
    int val=0,semn=1;
    while(s[p] == '-'){
        p++;
        semn = -semn;
    }
    if(s[p] == '('){
        p++;
        val=expresie();
        p++;
        return semn*val;
    }
    while('0' <= s[p] && s[p] <= '9'){
        val = val*10 + (s[p]-'0');
        p++;
    }
    return semn*val;
}

int main()
{
    in >> s;
    out << expresie();
    in.close();
    out.close();
    return 0;
}